Fertilization in ewes treated with progesterone and equine anterior pituitary extract.

Abstract

In recent experiments in which large numbers of fertilized eggs were required on specific days, 30 Merino ewes experiencing regular oestrous cycles were treated with progesterone to control the time of oestrus and ovulation, and with an equine anterior pituitary extract (HAP) to induce multiple ovulation. Progesterone was administered daily (10 mg/day i.m.) beginning on the 8th to 12th day of the oestrous cycle and continuing for 6–8 days. HAP, prepared as described by Moore & Shelton (1964), was given as three equal, daily s.c. injections (24 mg./day) beginning on the day before the final progesterone injection and ending the day after the final injection of progesterone. The ewes were run with Merino rams and were inspected for oestrus at 12-hr. intervals after the conclusion of treatment. All 30 ewes were served after treatment and the time between the end of progesterone treatment varied from 36–84 hr. Laparotomies were performed